I originally installed omweather 0.17 on my N800, then upgraded to 0.17.1 and finally 0.17.2. Somewhere during that sequence, automatic weather update stopped working. I'm not sure whether it was after the .1 or .2 bump. I could still update manually, but otherwise the desktop forecast never changed (even when the days advanced with the calendar).

To borrow a phrase from an academic research friend:
"Data, unlike wine, does not age well." ;-)

I decided to file a bug report, but first I uninstalled 0.17.2, did a power-off reboot, and reinstalled. That fixed the problem! Apparently the fresh install put the applet in a different state than upgrading in place. Obviously I can't guarantee this will work for everybody, but it's worth a try!

[EDIT: All my user specific settings (Location, Interface, Units) survived the uninstall/reinstall cycle, so this is a fairly painless test.]

One more thing: I also recommend trying the Grzankas icon set. The extra splash of color and dimensionality is quite attractive. If you don't like it, you can easily revert back to the default set.